Abstract: A new kind of silver colloid capped by 3-mercaptopropionic acid was prepared,and silver nanoparticles monolayer and multilayer films were fabricated on pre-modified gold electrode via self-assembly/electrochemical-assembly methods.The performance of this nanoparticle film was studied by cyclic voltammetry（CV） and electrochemical impedance spectroscopy（EIS）.As shown by experimental results,the modified electrode Ag-MPA/4-ATP/Au was more active than the others,and the electrochemical impedance was increased.The CV current of multilayer modified electrode（3（Ag-MPA）/2PDDA/4-ATP/Au） was higher than the monolayer modified electrode Ag-MPA/4-ATP/Au in 0.5?mmol/L K₃Fe（CN）₆ solution.The interfacial electron transfer is promoted.